/*******************************************************************************
* Copyright 2013
* Ubiquitous Knowledge Processing (UKP) Lab
* Technische Universität Darmstadt
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the GNU Public License v3.0
* which accompanies this distribution, and is available at
* http://www.gnu.org/licenses/gpl-3.0.txt
******************************************************************************/
package dkpro.similarity.experiments.sts2013.filter;
import weka.core.Capabilities;
import weka.core.DenseInstance;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Capabilities.Capability;
import weka.filters.SimpleStreamFilter;
public class LogFilter
extends SimpleStreamFilter
{
private static final long serialVersionUID = 1L;
@Override
protected Instances determineOutputFormat(Instances inst)
throws Exception
{
// Filter leaves the instance format unchanged
return inst;
}
@Override
protected Instance process(Instance inst)
throws Exception
{
Instance newInst = new DenseInstance(inst.numAttributes());
newInst.setValue(0, inst.value(0));
for(int i = 1; i < inst.numAttributes() - 1; i++)
{
double newVal = Math.log(inst.value(i) + 1);
newInst.setValue(i, newVal);
}
newInst.setValue(inst.numAttributes() - 1, inst.value(inst.numAttributes() - 1));
return newInst;
}
@Override
public Capabilities getCapabilities()
{
Capabilities result = super.getCapabilities();
result.enableAllAttributes();
result.enableAllClasses();
result.enable(Capability.MISSING_VALUES);
result.enable(Capability.NO_CLASS); // filter doesn't need class to be set
return result;
}
@Override
public String globalInfo()
{
return "A simple filter which applies the log function to all attribute values.";
}
}